Coupling-tapping machine.



J. E. BAKER; EENSBN (L4 MOWAT.

Ummm@ TAPPINQ MACHINE. 'APPLIOATIOE FILED 00T. 10, 1911.

Patented Feb. 3,191.4.

'l SHEETS-.SHEET 1.

(jh/ITN SSES J1 H. BAKER, E. HENSEN 6a 0; M. MOWAT'.

GOUPLING TAPPING MACHINE.-

- APPLIGATION HLED 002210, 1911. 1,085j85. Patented Feb. 3', 1914. A y '1 SHEETS-SHEET 2 G Q j;

J. H. BAKER, E. HENSEN E C. M. Mo-WAR CUPLING TABPING MACHINE.

APPLICATION FILED OUT. l0, 1911.

Patentad Feb. 3, 1914.

7 SHEETS--SHEET 3.

. w@ v Q, ...Rw x. uw m um, Il I w. E

@las INVENTQRS JW 9 wia WLM E. BAKER, E, HHSEN L G. M. MOY/VAT.

' GOUPLNG www@ MACHINE.

APPLIUATIO .FILED 00T* l0, 19H,

Patented Feb. 3; HEM

7 SHEETS-SHEET 5.

@www l y. wmi

J. H. BAKER, E. HENSEN 'dz 0. M. MOWAT.

GOUPLING TAPPIN G MACHINE. APPLIOATIQN'PILED ocT.1o, 1911.

Patented Feb. 3, 1914.

/UNTORS d. H. BAKER, E. HENSBN a 0. M. MOWT,

COUPLING TAPPING MACHINE. APPLIOAMON FILED 00T. 1.o, 1911.

Patented Feb. 3, 19M.

7 SHEETS-SHEET 7.

j #EIENTQRS 1 f. fm KM;

Wl? SSES n sinne aren FlC. i

JNATAHAN H. BAKER, EMIL HENSEN, AND OLIVER M. MOWAT, OF llviloK'liISP(3BE,v PENNSYLVANA, ASSGNRS TO NATONAL TUBE COMPANY, OF ITTSBUBGH, PENNSYLVANIA., A CORPORATION OF NEW JERSEY.

COUPLING-TAPPING MCHINE.

Specification of Letters Patent.

Patented Feb.' 3, 191% Application iled October 10, 1911. Serial No. 853,874.

To QZZ w71 om 'it 'may concern.'

Be it lrnovvn that we, JONATHAN H. Banicr., Emi. l'lnxsnx, and @LIVER M. lllona'r, citizens of the United `States, residingl at i/Icleesport, in the county of Allegheny and State oi Pennsylvania, have invented a new and useful Coupling-Tapping Machine, of which the following is a4 specication.

Our invention relates to apparatus'i'or tapping or cutting screw threads on the interior of :pipe couplings and similar. hollow c) mdrical erticles.

One object of our invention is to provide a multiple spindle tapping machine having novel means for simultaneously tapping a plnralil'y of couplings or like articles and another object of the invention is to provide a multiple spindle tapping machine having improved means for driving the plurality of taps employed whereby -the threads out hy the tapping operations are formed concentric 'witli the opening or hole through the couplings.

Another Aobject of our invention is to provi( c a tap holding mechanism having novel means' wherehy a slight vertical movement of the taps relative to the spindles is effected in nnscrewingthe taps from the' threaded couplings' and slripping or other d-.nnnge to the threads is avoided and prevented in unscrewing or removing the taps.

therefrom after completingY the coupling tapping' operations.

'further ohjcci ci' this invention is to .proride :i multiple Ispindle tappingimachine having coupling' gripping mechanism of novel construction whereby a plurality'of pipe couplinlcfsl are simultaneously gripped and :ire sccureliY held against rotation notwithstanding slight irregularities r inequalities in the diameter or Wall thickness in the couplings being grasped and whereiiv etoppnge or possible breakage or' other damage lo the apparatus hy reason of failure to hold one or more of a 'series of couplings in engagement with the gripping mecha? nisni is overcon'ie and prevented.

A still further ohjeci ofthe invention is to pro'ide a multiple spindle tripping inachine haring the novel combination and arrangement of parts 'as will more fully appear hereinafter.

Referring to the accompanying drawings l the spindles.

if'orxning,y part of this specification5 .Figure Il. is a fromJ elevation showing anuiti'ple spindle iapping machine. constructed and arranged 11i-accordance with our invention. 'Fig 2 1s a. sectional side elevation oi? the apparatus shown. in Fig. l. Fig. 3 is a sectional plan on the ,irregular line vIlle-'lidi v of Fig. l, showing the gripping mechanism by which the couplings are grasped and held against rotation. Fig. 4 is a. detail sectional side elevation sl'iowingt-he spindle feeding ineehanisrnin its raised or inoperative position. Fig. 5 is a detail sectionall side elevation showing the spindles in lowered posit-ion, or position at or about the completion of the coupling tapping operations. Figf is a. front elevation partly in section showing' adetail of the spindledriving mechanism and the' feed mecl'ianismby which the spindles are advanced or moved downwardly during the thread cutting p erations. Fie. 7 is a sectionalplan on the line. VI-VII of Fig. G. Fig. 8 is a sectional plan on the line 4VIH-VIH of Fig. il showing the arrangement of the slides and guide for the vertically movable cross arm forming the spindle supporting mechanism. Fig. 9 is e front eleva-tion slio\\'ing a detail ofthe friclion clutch oonnectionsl between thev driving motor and spindle driving shaftand the clutch opely ating mechanism. Fig. 10 is a sectional sido elevation oi the mechanism .shown in Fig. ll. Fin'. 11y is a detail elevation, partly in section, shi'nving; the (,-onstrnction `oilthe eh'nclr mechanism `for securing' the laps in place on Fig. 12 is a, sectional plan of the apparatus shown in Fig. il. the 'section being taken on the `line Kil-XH of Fig'.

111 Fig. l2, the section being taken on` the line XHI XIII of Fig. l1.

ln the drawings, .Q designates the hase pleite of the taping machine which is secured in the. desired location on a suitalile inundav tion provided for that purpose. 'The hase ilaie, as' .shown is irovided with u nvarillv.

cxtenilingr'finngeson its marginal edges and with depressed portions forming an oil pan or trough. Housings or standards y'which are bolted or otherwise secured to the hase plate have their upper ends rigidly fastened together by the horizontally extending cro-fis arm 4, this cross arm,'wh1ch is stationairy,

Fig. 13 is a sectional plan similar to also serving to support or carryY the vertically movable spindles 5 and spindle rotating mechanism. The front face of the cross arm 4 is provided with bearings 6 and 7 in which the tap carrying spindles 5, 5,.5, 5d, 59, 5f, 5g, 5, are mounted so as to be'verti7 cally movable as well as rotatable. The lower portions of the spindles 5, which ex7 tend through the bearings 7, are enlarged in diameter and are lprovided with axially extending recesses or holes.

A rod or bar 8 having-a tap holding chuck 9 on its lower end is inserted in the axial opening or recess in the lower end of each spindle 5. These bars 8 are secured at their upper ends by pins 9n to the spindles 5 so as to be'positively turned or rotated there-r with. Taps 10 which may be of any one of various sizes depending upon the sizeof the pipe couplings to be threaded are detachably secured in the tap holding chucks 9.

In the construction of the tap holding chuck 9, (as will be best seen by reference to Figs. 4, 11, 12 and 13) the lower ends of the rods 8in the hollow spindles 5 have a hollow driving head 95 secured thereon by a pin 96. yThe bottom edge of the head 95 has a transverse recess or groove 97 therein, the bottom surface 97 of which is inclined lengthwise. Secured in the axial opening of the driving head 95 is a hollow tap driving collet 98, havingradially extending shoul ders 0r lugs 99 projecting from opposite sides of the center thereof. The lugs 99 project into the recessl 97 and by engagement with the sides of the recess 97 in the lower edge of the driving heads 95 are positively rotated by the heads when the heads 95 are rotated by the spindles A collar or cap 100 is secured to the lower ends of the heads to retain the collets 98 in place in the heads 95, 'being held in place by the screws 101 which extend into thel slots 102 in the collars or caps 100 -and prevent relative vertical movement'while permitting a limited axial movement of the collar on the driving head 95. The Shanks of the thps 10 are secured to the collets 98 by pins 102 and a slotted recess 103 in the bottom of the collars :pen mits the collets 98 to be removed from the driving head 95 when the collar 100 is rotated into the proper position on the head 95.

The rods 8 are made slightly smaller in diameter than the longitudinal openings in the end of the spindles 5 in which thev are placed so to permit the taps 10 to float or rotate in a path slightly eccentric to the axes of rotation of the spindles 5. This ec centric movement of the chucks and rta-ps enables the individual taps to cut. threads concentric with the interior of p .-e couplings or other articles when not in exact alinenient with the vertical axis of the conplings.

Each spindle 5 is provided at an inten noemen mediate point in its length with a spur gear 11 keyed theretowhich meshes withiand is driven by one of thefour wide face spur pinions 12 vhich are keyed or otherwise secured on pinion shafts 18 rotatably mounted in bearings 14 and 15 on the cross arm 4.

A horizontally extending vertically movable ucross arm 1G by which the spindles are caused to move in unison in a lengthwise or vertical direction, is provided in front of the stationary cross arm 4, bearings 17 on the rear face of the cross arm 16 connectingr the upper ends of the spindles 5 to the cross arm 16. Collars 18 are secured on the upper end of the spindles l5 to engage with the opposite ends of the bearings A17 and maintain the. rotary spindles in place on the movable cross arm 1G. The cross arm 16 has a guideway 19 engaging the slide 20 on the front face of the stationary cross arm 4 to cause the cross arm 16 to move in a path parallel with the vertical axes of the spindles 5 which slide lengthwise in the spindle bearings 6 and -7 during the coupling tapping operations.

The upper end of each pinion shaft 13 is provided with a bevel gear 21 which meshes with one of the smaller bevel gears 224011 the horizontal driving shaft 23 which is provided at intervals in its length with bearings 24 secured on the top of the cross arm 4. The spindles 5 are arranged in four pairs, 5tL and 5b, 5 and 5d, 5e and 5f, 5g and 5h, each pair being driven by one of the wide faced spur pinions 12. The spurpinions 12 have faces of sufficient Width to mesh with'the gears 11 and drive the spindles 5 when in any position Within the range of vertical movevment 'of the spindles.

A reversing friction clutch 25 is employed to operatively connect the spindle driving shaft 23 to the spur gear 26 .loosely mounted on the shaft 23 and connected by the gear 27 and train of slow down gearing 27 with the driving pinion 28 on the armature shaft of the driving motor 29 in. driving the shaft 23 and spindles `in -one direction. The clutch 25 is also arranged to operatively connect the spur gear 30 with the shaft 23, this gear 30 also being loosely mounted on the shaft 23 and being operatively connected with the slow down gearing 27 so as to be' positively rotated in the opposite direction to the spur gear 26 by the constant speed, continuously rotating, driving motor 29.

The 'movable friction member ofthe frie- .V

tion clutch 25 is actuated by the lever 31 which is pivoted intermediate of its ends to the pin 32 on the stationary cross arm 4 andy thelowerend of the le'ver 31 is operativelyl l connected to the piston rod 33 of the double Locaties A pairiof gripping jaws 41, 42, is mounted in each slotforopening 40 so as to b e horizontally'movable therein, each j aw being adjustable toward and away from its opposing jaw and the jaws having inserted bits engaging with the couplings so as to permit pipe couplings of various sizes being held in axial alinement with the spindles. The jaw members 41 of each pair areadjustably held in the slots 40 by the adjusting screws 43 and lock nuts 44 are employed to secure the screws 43 in adjusted position. The opposing jaw members 42 of each pair are connected by adjusting screws 44a to one end of the sliding bars 45 movably secured on the top of the table 39.- The opposite end of the bars 45 are pivoted to one end of the toggle links 46 and one end oi each ot these links 46 is pivotally connected to one end of the toggle links 47 and to the toggle actuating bar 48 by `pins 49. One end of each toggle link 47 is pivotally connected to springfollowers 50 mounted in the front end of the spring b'oxes 51 which are secured to the rearside of the table 39.

A helical spring 52 is located in each springV box 51 between the front followers 50 and rear followers 53 and an adjusting screw 54 is secured in the rear end of the boxes 51 to vary the amount of compression on the springs and enable the couplings being yieldingly held against rotation between the jaws of the gripping mechanism during the tapping operations. This construction with the removable bits in the jaws which engage the surfaces of the couplings alsov permits a plurality of the couplings, which may vary .slightly in diameter, to be simultaneously grasped and held by pairs of gripping jaws which are actuated all at the same time by nie-ans ot' the reciprocating toggle connecting bar 48 to which the meeting ends of theA toggle links 46 and 47 are pivotally attached. Secured to the under side of the table 39 are brackets 55 each supporting a vertically extending pin or post 56 below the slotted openings 40 in the table and in vertical alineineut with the spindles 5 (see Fig. 2). Vertically moi-'alle coupling supporting sleeves 57 are loosely mounted on the upper ends of the posts 563 which are held in their ,lifted position on las posts by engagement with one end of the oounterbalancc levers 58 pivoted by pins 59 on the brackets 55. The opposite ends of the levers 58 have counterweig'nts 6() of sufficient weight to hold the sleevesT in raised position and support couplings placed between the pairsof gripping jaws 41, 42, when the movable gripping jaws have been retracted intoftheir disengaged position. f

Occasionally, one or more of any series ot couplings 'being tapped will be so much smaller in diameter than others in the same seriespas to not be grasped and held against rotation by the gripping jaws, and as the taps are advanced positively by the lead screw 7 0 during the coupling tapping operations, unless preventive means are employed serious breakage or other damage to the apparatus will follow when a loose coupling is engaged by the advancing end of the tap.`

The couplings being yieldingly held against vertically downward movement between the pairs of gripping jaws 41 and 42 by the counterweighted sleeves 57, a coupling when so loosely held as to turn with the tap engaging with itstop edge will be forced downwardly with the sleeve by the positively advancing tap 10 and cause the counterweight (20 to lift, so as to in this' way prevent otherwise possible serious damage to the apparatus.

The ends of the toggle connecting bar 48 are secured t the pistons or plungers 61 and 62 whichare -secured in the toggle actuating cylinders 63 and 64 mounted on the sides of the housings 3. The cylinders are provided with the usual stutling boxes in which the glands G5 are secured to hold the cylinderl packing in pl ace.

The vertically movable cross arm 16 is flexible connections 35 being attached thereto. The cables 35 arev passed over lsheave wheels or pulleys 36 reyolubly mounted on the tops of bearing stands 37 which are fixed to the top of' the stationary cross arm 4 and the other ends of these cables 35 are secured. to the counterweights 38. The counterweights 88 are made of suilicient Weight to more than balance the movable crosshead 16 and parts att-ached to and movable therewith so that unless-held or restrained, the counterweights 38 will lift the cross arm 16.

A horizontal table 39 on which the couplings are supported during the tapping operations is rigidly. secured in place below the spindles 5 on brackets 3a formed integral with the lower portion of the housings 3. This table is provided with a series of slotted openings or holes 40, one of these `openings being located beneath each of the spindles 5.

`counterbalanced, one end of the cables or y los lMounted on an upwardly extending sup- A port- 66 secured to the stationary cross arm #is a Huid pressure cylinder 67 having a downwardly projecting piston 68 to the lower end of which the vertically adjustable cross arm 16 is secured through the guide way 19. The cylinder 67 is arranged to quickly move the cross arm 16 with the spindles 5 and other attached parts downwardly sufliciently to` bring the lower end of the taps 10 into engagement with the couplings or other articles to .be tapped. A manually operated valve 69 is provided to connect the upper end o1',l the cylinder 67 with a source oi'rlluid pressure and is arranged in such manner to admit andfshuto fluid presof fluid pressure from the cylinder' when the crosshcad is to he lifted into its raised position hy the counterw'eights 38;

A. vertical lead screw gli) is mounted in hearings Z1-724m the stationary cross arm f i and keyed or otherwise secured to the lower end of this lead screw is a spur gear wheel 73 which meshes )with and'is driven by the train or". slow downgears 74, rotatably secured 4by stub shafts or pins to the under side of the cross arm il. The slow down gears 7s are driven hy the spur pinion- 75 which is secured on the lower end of one of the pinion shafts 13 for the spindle driving pinions 12. (See Figs. l and 6).

il' half nut` 76 pivotally secured .to the movable cross arm 16 employed to operatively connect this crossfarm with the lead screw 70 is arranged to he moved into engagement with the screw threads on the lead screw 5 in, the coupling tapping operations and in the reverse or upward movement necessary to unsere-w the taps from the threading couplings at the completion. of each tapping operation. The lower end i' the vpivoted half nut. 76 is connected by means of a linlr 77 to one end of the bent lever 78. which is pivoted at an intermediate point in. its length to the lug 7 9 on the movahle cross arm 16. The lower end 78El of the lever arm 7811s providedv with a handle by which itis lifted to move the half nut 76.

-into operative engagement with the lead Atending from the stationary cross arm 4 isl a vertical post 82 having' a trigger 83 on its upper end. 'lhistrigger 83 is arranged to tilt when the inclined face of the tilting latch 79 engages therewith in the downward movement oi' the cross erro: lli so as to permit the latch '79 to pass the trigger 83 freely. The helical spring Sil is'secured to one end l of the trigger' Q3 to return it to the position A shown in Fig. (i, after heing tilted bythe latch- 79. The I:'igger 83 is adjusted vertically with its post S2 so as to engagewith the oilset or jog '79 on the outer end 0f the tilting latch 79 and trip this latch at the desired point inthe upward movement of "the cross arm 1G and ta s 10. as the cross arm 1G is being lifted hy t 1e ation of the lead screw 70 to release'the lever arm 78 and U disengaged from the tapped couplings.' The insures bracket onthe cross arm 4 is'also provided 'with a vertical post 85 which is vertically 'adjustable and which will engage with the handled portion 79E ofthe.` latch' 79 when the cross arm 16 has reached the extreme limit of its downward or tapping movement and will disengage the latch trom the upper end of the pivotedlever 78, vso as to cause disengagement" o the half nut and lead screw and prevent damage caused byfurther downward movement of the taps 10. When so released the weight of the lever 78 causes it to move hy gravity from the position shown in Fig. 5 into thatshown in Figs. 2 and et, and by euch movement disengage the half nut 76 from the screw threads of the lead screw 70.

Secured to one end ofthe horizontal vertically moving cross arm 16 is a. downwardly extending Arod orshaft 86 having dogs or tappets S7 and 88 adjustahly securedv at separated points thereon. The valve 89 which is'operatively connected to the oppo site ends of the-.Huid pressure cylinder 34- l used in operating the reversing friction clutch 25, is provided with a lever 90 having a pin 91 pro3ecting.fro'in its outer end. This pin 9:1 extends outwardly so as to be engaged by the tappets 87 and 88 so as to move the lever 90 and through the valve stem manipulate the valve 89to admit uid pressure to one end or the other of the cylinder 34. A rod 92 which engages with a helical spring in the rod support 93 on the cross Aarm 4 has its upper end arranged to engage with and frctionally hold the valvestem and its lever 90 in any position to which it is moved by the tappets 87, and 88 during the operation of the apparatus.

vThe operation of the apparatus ispas o1- lows: The chucks 9 are supplied with taps 10 of the required size. Thev change gears are adjusted by the handle 94 projecting from the change gear box so as to cause the spindles 5 and the lead screw 70 'to rotate at a speed corresponding to that required in cutmanually shutting od the supply of fluid' pressure to the operating cylinder 65. VThe counterweights 35 being of' sufficient weight.v to more than counterbalance'the cross arm 27, this arm is quickly raised or lifted 'into'y its retracted position (that shown fin Figs. 1, 9, and 4) when the supply of fluid pressure is shut oil from the cylinder 65. Untapped weones couplings are then placed'in' position beiwecn each pair ot" cli-acting gripping jaivs lL-42,' when ,fluid pressure is admitted to the jaw operating cylinder located on the left of Fig. B and the toggle connecting arm is moved fromA right to left. (Fig, 3) such movement causing the gripping jaws to grasp and hold the couplings in place on the coupling supporting table The operator then manipulates the operating valve 69 anually so as to admit Huid pressure to the cylinder 65 and causes the plunger titi in this cylinder to move the cross arm 16 downwardly into a position which will bring the lower ends of the taps l secured to theV lower end of the spindles 5 in close proximity to the upper ends of the couplings to be tapped. The halt" nut 76 is then moved manually by lifting the lever arm T8 so as t-o be in engagement with the screw threads on the lead screw T0 and the movable cross arm 16 and spindles 5 supported therefrom are caused to move downwardly at a rate of speed corresponding to the pitch ot the threads being cut on the couplings b v the taps. Vlllien the taps l0 engage with the upper ends of the couplings being tapped the lugs 99 on the collets 98 are moved in the. slots or grooves 91' inv the bottom edge ot the driving heads 95, this movement'causing the lugs hy 'engagement with the inclinedhotlom surlare D?"- ot' the grooves 97 to more the collets PH into the position. shown in ll. ll'vlien in such position further relative movement of the colleta and driving heads prevei'itcd iiuring'tho tapping operations. .liter the Ai'eed screw has moved the taps thriiiugh the couplings so as to forni the. threi ds thereon the upper ta'ppety or dog 88 will have` moved the valve lever 90 into position to admit liuid pressure to one end of the cylinder so as io cause the piston 33 in the cylinder to actu-ate the clutch lever .31 and throw the clutch into position to reverse the-direction ot' rotation of the spindle driving shaft 23 and spindles 5. thereby causing the taps to back out "".or unscrew from the then tapped or threaded couplings. Should, for any reason, the clutch fail to operate to reverse the spindles when the operation of tapiing the couplings has been completed, continued movement ot' the cross arm 16 will cause the handled end 79a of the latch 79 to engage with the upper end of the Vpost oi rod 85, and by such engagement trip the latch 79 and cause. the half nut to be disengaged from the lead screw 70, in this way preventing further downward movement of the tapping spindles. After the tapping machine is reversed, (when the spindles will be rotated in` a counter-clockwise direction), to unscrew the taps from the tapped couplings the spindles 5 and driving heads 95 at the beginning of the reverse movement move axially relatively to thecollet 98. This movement shifts the collet lugs v9 in the grooves or recesses 97 until in engagement with the opposite end 'of the grooves trom that shown in Fig. 11, so that a light vertical movement ol' the collet in the head is effected and stripping ot the threads in the couplings in unseren-'ing the taps therefrom is avoided and preyented by permitting the slightI vertical movement ot the tap independent of the movement ot the spindle and driving head. As the feed screw 7() moves the cross arm 16 upwardly the trigger 83 engages with the jog or odset T9 on the outer end of the tilting latch 79 and further movement of the cross arm will trip the latch Tf) so as to release the lever arm 'T8 and disengage the half nut Y6 from the lead screw 7U. After the taps are unscrewed or lifted to be clear of the couplings and the latch 79 has been tripped, the taps and spindles are then more rapidly lifted by disengagement ot the half nut from the lead screw and by shutting oil' Huid pressure from the upper and of the cross arm actuating cylinder 65, the co-unterwcights 3:5 acting to quickly lift the cross arm The tapped couplings are then removed from between the gripping jaws and replaced by other untapped couplings. The cross arm is then again caused to descend after the gripping mechanism is caused to grasp the new lot of couplings until the taps are engaged hy the upper ends ot' the couplings The advantages ol our invention will be apparent to those skilled in the art, By 'moans oi our improved coupling gripping meclianisn'i the couplings are i,'ieldingly held against. rotation during the tapping operations.

The gripping mechanism is easily and quickly adjusted to suit couplings of various sizes. The coupling tapping mechanism is adapted Jfor quick adjustment in' moving the spindles to bring the taps into and out of cutting position relative to the couplings.

Modifications in the construction and arlrangement of the parts may be 'made without departing from oui` invention as defined in the appended claims.

lVe claimzl. In a tappingmachine the combination with a plurality of rotatable, lengthwise movable spindles, having taps von one end thereof, of mean-s for simultaneously moving the spindles lengthwise to bring the taps into engagement with the articles to be tapped, independent means for'simultaneously moving the spindles lengthwise arrange-d 'to control and cause lengthwise travel ot the spindles at a speed corresponding to the pitchv of the threads being tapped, and mechanism for simultaneously moving said spindles and taps lengthwise out o engagement with said articles.

2. In a tapping machine the combination OHS lil spindles and taps lengthwise out of engagement with said articles andmechanism arranged to detach the 'independent s indle moving means after a pre-determined ength of travel.

3. lnla tapping machine the combination' ity ot rotatable, lengthwise with a plura movable spindles, having taps on oneend thereof, ot means for simultaneously moving the spindles lengthwise to brin into engagement with the articles to ous y moving ranged to control and cause lengthwise travel of the spindles at a speedcorrespond-.

ing to the pitch of the threads being tapped,

mechanism for simultaneously moving said spindles and taps lengthwise out of engage ment with said articles, mechanism arranged to detach the independent spindles movmg means after -a pre-determined length ot' travel and a safety mechanism arranged to limit the downward travel of the spindles. Alf. ln a pipe coupling tapping machine,

the comhination with a plurality of rotatable I and lengthwise movable spindles having taps on one end thereof and gripping mechanism arranged to gras and hold a plurality ot 'couplings against rotation while being tapped, oi" mechanism for simultaneously moving the spindles lengthwise into engagement with the couplings, means for moving the spindles and' taps out oaf engageu Aes ment therewith and a second spindle moving mechanism having independent means for moving the spindles simultaneously lengthwise during the thread cutting operations, said second mechanism beingv ajrranged to reverse the direction of movement of the spindles after cutting a predetermined length of. thread on the couplings to move the spindles upwardly at a speed coiresponding to the pitch .ot the threads on the taps accused to the spindles.

the ta sg nism' for rotating the spindles and means tapped, independent mea-ns tor simultanethe spindles lengthwise ar-` weaves l 5. In a tapping machine, the combination with a plurality of rotatable and lengthwise reciprocahle spindles having taps secured to one end thereof and gripping mechanism ar- .ranged to, grasp and hold a plurality of couplings against rotation while being tapped, of means for simultaneously reciprocati'ng the spindles lengthwise, independent means for simultaneously" imparting lengthwise movement to the spmdles, means arrangedto reverse the direction of movement of the spindles after cutting; a predetermined len th of thread on the coutor imparting a simultaneous lengthwise movement to the spindles, of a plurality of sets olz gripping jaws arranged .to grasp and hold couplings against rotation vdurin the tapping operations and means for yieldingly supporting the couplings in position between the 'retracted ,gripping jaws, said supports being arranged to yield and move downward with a coupling loosely supported thereon while other ofthe couplings engaged by the gripping jawsy are being tapped.

ln a tapping machine a spindle having a driving head thereon, a tap secured in said driving head., means on said head permitting' a limited lengthwise and axial movement ot the tap relative to said drivin head. and means for securing the tapl to said spindle.

*8. In a tapping?, machine a spindle having a driving head thereon, a tap holding collet in said head and means for .detachably securing the collet to saidhead, said collet and head having means co-acting to permit a limited axial and lengthwise movement oit the collet in said head. l

In testimony whereof, we have hereunto vset our hands,

tilt

lll@ 

